Reference is made to my previous application for a Precast Concrete Building Construction, filed June 2, 1969, Ser. No. 837,986. Disclosed in the previous application is a multiple story structure primarily adapted, but not limited, for use as a parking garage, the structure utilizing a set of precast reinforced concrete units or modules, each comprising a slab and four supporting legs. These are set side-by-side and end-to-end, as well as stacked vertically to form a multistory structure. The units are secured together horizontally and vertically by post tensioning tendons which may, if desired, be released to permit disassembly and removal to another location for reuse. A successful multiple story garage structure has been built in accordance with the disclosure in the previous application.
The present invention is directed to a further development of the previous structure, and is summarized in the following objects:
First, to provide a demountable multiple level building structure wherein a first set of elongated precast concrete modules having supporting legs are so positioned in spaced relation that a second set of precast concrete modules coextensive in length but without supporting legs may be positioned in the space provided between the first set of supporting modules for support thereby.
Second, to provide a multiple level building structure, as indicated in the previous object, wherein the supporting modules may be so spaced as to receive supported modules endwise, or supported modules of extra width, therebetween to provide extra spacing between the legs of adjacent supporting modules; each such extra wide supported module, if its span requires, being provided with tendon chases or guideways of catenary profile contained within the slab itself or extending into underlying beams should the module be so provided.
Third, to provide a demountable multiple level building structure which incorporates a novel means and method whereby the second set of supported modules, whether standard or of extra width, may, if desired, be cast in situ yet are capable of later disassembly, and wherein a supporting form may be used to cast an uppermost module, then lowered to cast the module next below.
Fourth, to provide a demountable multiple level building structure and method of construction wherein, should selected supported modules be cast in situ, the tendons are first threaded through the precast modules and span the spaces to receive in situ cast modules; and, wherein the exposed or spanning portions of the tendons are covered by novel sheaths which, after the modules are in situ cast therearound, permit sliding movement of the tendons for tensioning, as well as subsequent removal should this be desired.
Fifth, to provide a demountable multiple level building structure, as indicated in the preceding objects, wherein selected modules of the second or supported set may be provided at their ends with novelly arranged extensions and recesses for effecting end-to-end connections and mating transversely extending chases or guideways for receiving post tensioning tendons inserted after assembly to tie the modules in their end-to-end relation.
Sixth, to provide a novel means and method of forming tendon guideways or chases in precast concrete modules wherein an elastically yieldable metal core member of predetermined longitudinal profile is covered with an elastomeric sleeve, is then positioned in the form used to cast the module and finally, after the module has sufficiently cured, the core is first extracted, the core being sufficiently yieldable elastically to permit this operation, whereupon the elastomeric sleeve is readily extracted.
Seventh, to provide a multiple level building structure and method of construction, wherein the supporting modules are provided with vertical tendon guideways formed in the legs and overlying slab portions thereof, corresponding guideways of a stacked set of supporting modules being disposed in vertical alignment to receive a common tendon.
Eighth, to provide a structure, as indicated in the preceding object, wherein the vertical tendons apply a compressive force on the supporting modules having a component which increases the load carrying capacity of the beam of each supporting module extending between the legs thereof.
Ninth, to provide a structure, as indicated in the other objects, wherein the mutual engaging surfaces of the supporting and supported modules are secured in fixed mutually bearing relation by the vertical and horizontal tendons so that the modules react to loads as a single unit.
Tenth, to provide a multiple level building structure having novel marginal precast concrete spandrels arranged for ready installation and providing a partial form for casting in situ a marginal walkway.